Impact of Climate Change on Extensive Pastoral Lands

The Effect of Global Climate Change on Extensively Grazed Pastoral Lands: Comment and an Approach to Assessment and Forecasting.

Peter S Harris, Pastoral Resource Assessment Specialist

Evidence and forecasts of climate change have led to a groundswell of concern and action on ways to reverse detrimental trends and mitigate negative effects on the environment. The effects on agricultural and pastoral lands have become the focus of many international organisations primarily under the auspices of the United Nations Framework Convention on Climate Change. The basis or foundation of action on climate change are the reports by the Intergovernmental Panel on Climate Change (IPCC) and impetus given by the intentions and declarations of the Kyoto Protocol.

Even a casual glance at the colour distribution in the following maps, particularly of the yellow and orange shades highlights the world-wide seriousness of climate change forecasts on environmental quality, conditions for living and, the capacity for agricultural and pastoral food production.

The mitigation of detrimental climate change as it relates to agriculture and livestock production is described in detail in the IPCC Fourth Assessment Report: Climate Change 2007, Chapter 8[1]. Monitoring and assessment of such changes is part of the extensive FAO Climate Change Programme[2].

There is a plethora of documents and reports on the impact of global climate change on soils, land cover and land use as they relate to areas currently used for pastoralism, both intensive and extensive. However, there is a marked paucity of consideration of the direct impact of the changes upon pastoral resources and production in terms of scale and quantity. In my opinion this is a serious shortcoming from both environmental and livelihoods view points. Particularly so, since extensive pastoralism accounts for 25% of land area, producing 10% of the world’s meat and supporting approximately 20 million households[3]. According to one estimate, in Africa alone more than 100 million people are involved in the pastoral economy[4].

Regarding the impact of climate change on pastoral activities within extensively grazed grasslands and shrub lands:

The effect of the changes on pastoral resource condition and productivity needs to be assessed so that the changes can either be accommodated or mitigated, at national to local levels.

Drawing upon the most up-to-date information, forecasts of the impacts of climate change need to be quantified in terms of both resources and production, according to a range of realistic impact scenarios.

The feasibility of the numerous proposals for carbon sequestration on these lands and any impact of those actions upon current pastoral production practices and pastoralists’ livelihoods needs critical evaluation and assessment.

Decades of development projects on extensively grazed pastoral lands have demonstrated that management interventions, while technically feasible, have been very difficult to implement successfully. The majority of the carbon sequestration enhancement techniques that are being proposed have been components of these historical development programmes.

Another issue is the reconciliation of detrimental impacts of climate change with the increasing demand for livestock products by a rapidly increasing human population. Commensurate increasing livestock populations are illustrated in the following figures, worldwide and for specific countries. The more rapidly increasing livestock numbers in developing countries is of special note. How are these trends affected by climate change, now and in the future?

The majority of extensive pastoral lands are characterised by high levels of spatial and temporal heterogeneity. While variability is a feature of all agro-ecological zones, it is particularly marked in the extensively grazed pastoral lands. The following figures use rainfall and remotely sensed data as indicators of variability of forage growth in typical extensive grazing lands.

Rainfall variability in drier climatic zones translates into variability in annual livestock support capacity. This is illustrated for pastoral systems with “neutral” and “negative” long term trends in the following figures.

Modelled 100 year trends in annual livestock support capacity (source this author)

These fundamental characteristics must be taken into account when assessing the impact of climate change, evaluating mitigation and management measures, and determining the viability of any associated carbon sequestration programmes.

Since the late 1980s the decision support software package now known as RAPS[5] has been used to assess complex extensive pastoral systems. RAPS, in its current form, is suited as a decision support tool for the integrated assessment of the impact of global climate change; relating land and forage resources to livestock support capacity and production. RAPS integrates pastoral system complexity and dynamics, including the analysis of current and forecast long-term trends, and can be linked with other ecosystem modelling and land assessment tools.

The software was developed in parallel with many international consultancies undertaken by this author, primarily under the auspices of the FAO and other UN organisations. A major catalyst for the initial development of RAPS was the realisation that traditional methods of assessing pastoral lands had serious shortcomings, particularly in relation to understanding system complexity and dynamics, and the impact of development components on the overall system.

Major milestones in the development of RAPS software are: successful application in a wide range of environmental and developmental scenarios leading to realistic and practical decision support; use in an award-winning[6] analysis of the pastoral resources of Minqin County, Gansu, China; the translation of an earlier version of the software package into Chinese, and; the application of RAPS in case studies described in the FAO book Grassland resource assessment for pastoral systems, Plant Production and Protection Paper 162, written by this author.

The RAPS Users Manual gives an overview of the programme’s current form, scope and sophistication. The manual may be obtained upon request.

Although RAPS was initially developed for personal use, its capabilities as a practical decision support tool indicated a potential for wider application. The software is available for download and its use is without charge.

RAPS can complement present land-based climate change programmes by focusing on pastoral resource condition and trend, and livestock production components. For example, it may be used in association with the CENTURY/ DAYCENT ecosystem modelling systems, that interpret C, CH4 and N2O, and, particularly, primary production. Similarly, RAPS may be linked with the FAO-MOSAICC (Modelling System for Agricultural Impacts of Climate Change) which assesses the impact of climate scenarios on crop yields.

If these models, or similar, generate quantitative primary production trends as affected by climate change, then such data would be used by RAPS to model of trends in livestock support capacity and above ground biomass net of consumption (including sequestrated foliage C).

Similarly, if the CENTURY or MOSAICC models generate primary production data as influenced by carbon sequestration improvement measures, then the impact of those measures upon livestock support capacity can be assessed using RAPS.

A specialist function of RAPS is to identify and quantify pastoral resource component complementarity. Managing a heterogeneous mix of forage and land resources typical of the majority of pastoral systems results in “system benefits” such that the livestock support capacity of the whole system is greater than would be the case if the forage resource units are each managed in isolation: “the whole is greater than the sum of the parts”. Further information on the concept of pastoral resource complementarity may be found at http://pastoralsystems.co.nz/?page_id=848.

Within the context of climate change and carbon sequestration, experience to date indicates that the analysis of resource complementarity would be a useful tool for identifying and prioritising land units for carbon sequestration measures. Measures that may negatively affect or compromise livestock production could be assigned to land units that previously exhibit less positive complementarity and therefore minimise the impact upon traditional pastoralism.

RAPS data requirements are flexible, can utilise information from a wide range of sources and quality, and be updated and refined easily. It can operate over a wide range of spatial scales. Typical types or sources of input data are: land and forage statistics; condition and trend monitoring data; livestock statistics; climate records; remote sensing; GIS data; historical and forecast information; convergent indicators used to maximise reliability and certainty, and, not the least; herder and farmer experience and advice.

Comprehensive lists of RAPS uses and the scope and forms of output are presented in the related links mentioned above. Within the context of the assessment of the impact of global climate change, the following are relevant examples of use:

Forecasts of trends in pastoral resources and livestock support capacity, incorporating system dynamics;

Augmentation or extension of current programmes and environmental modelling that focus on other aspects of the impact of climate change.

The technique described above, and via the links, is sufficiently advanced, field tested, realistic and practical, to further contribute to the management and sustainable use of extensive pastoral lands. This is particularly so in countries where pastoralism is threatened by serious environmental challenges such as caused by climate change.
Peter Harris 2014

End notes

[1] http://www.ipcc.ch/publications_and_data/ar4/wg3/en/ch8.html

[2] http://www.fao.org/climatechange/49381/en/

[3] http://www.odi.org.uk/work/projects/pdn/eps.pdf

[4] http://www.cultura21.net/karamoja/docs/Ali_Wario.ppt

[5] Resource Assessment for Pastoral Systems. To indicate its complexity and level of development, RAPS is composed of about 30,000 lines of code. RAPS development has never been a commercial undertaking.

[6] Denghuang Prize awarded by the Gansu Provincial Government for contribution to economic development, science and technology, education and training.